Glass laser discs with annular alkali lead borate coatings and uses thereof

Abstract

A laser assembly that includes a novel glass laser disc having an annular alkali lead borate glass coating for use in the assembly is disclosed. The annular coating has an index of refraction that is about 3 to 12% greater than the index of refraction of the laser disc, the thermal properties also being sufficiently matched with the glass laser disc so as to prevent the development of undesirable strains therein, the glass coating comprising a mixture of alkali metal oxides in which at least two different alkali metal oxides are present, and any K 2 O that is present is limited to an amount of not substantially more than about 1% by weight and an effective energy absorbing amount of heavy metal oxide that absorbs energy at a wavelength of about 1.06 microns to prevent parasitic oscillations. The heavy metal oxides include oxides of transition metals of the 3d, 4d, 4f, 5d and 5f orbital series.

What is claimed is: 
     
       1. A laser assembly comprising means for providing a source of pumping light; means defining an optical resonant cavity for the lasing material including a housing; means for holding a glass laser disc in the housing; and a glass laser disc capable of excitation into a metastable high energy state and stimulated emission of electromagnetic radiation therefrom, the glass laser disc located within the housing and positioned along the optical axis of the laser, the disc having an annular lead borate glass coating capable of absorbing energy at a wave length of about 1.06 microns to thereby absorb any parasitic oscillations, the glass coating having an index of refraction of about 3 to 12% greater than the index of refraction of the laser disc, the disc and coating being so constructed and arranged that the thermal expansion and contraction of the coating are sufficiently matched with the glass laser disc so that the development of undesirable strains in the disc is prevented, the glass coating comprising a mixture of alkali metal oxides in which at least two different alkali metal oxides are present, and any K 2  O that is present is limited to an amount of not substantially more than about 1% by weight, and an effective energy-absorbing amount of a heavy metal oxide that absorbs energy at a wave length of about 1.06 microns. 
     
     
       2. A laser amplifier assembly comprising means for providing a source of pumping light; means defining a cavity for a lasing material including a housing; means for holding a glass laser disc within the housing and positioned along the optical axis of the laser amplifier; a source of monochromatic light; and a glass laser disc, the glass disc capable of excitation into a metastable, high energy state and stimulated emission of electro-magnetic radiation therefrom, the glass laser disc located within the housing for causing stimulated emission when the monochromatic light is passed therethrough, the disc having an annular coating, the coating comprising an alkali lead borate glass capable of absorbing energy at a wave length of about 1.06 microns to thereby absorb any parasitic oscillations, the glass coating having an index of refraction of about 3 to 12% greater than the index of refraction of the laser disc, the coating and disc being so constructed and arranged that the development of undesirable strains in the disc is prevented, the glass coating comprising a mixture of alkali metal oxides in which at least two different alkali metal oxides are present, and any K 2  O that is present is limited to an amount of not substantially more than about 1% by weight, and an effective energy-absorbing amount of a heavy metal oxide that absorbs energy at a wave length of about 1.06 microns. 
     
     
       3. A laser assembly as defined in claim 2 in which the mixture of alkali metal oxides includes Na 2  O. 
     
     
       4. A laser assembly as defined in claim 2 in which the mixture of alkali metal oxides comprises Na 2  O and Li 2  O. 
     
     
       5. A laser assembly as defined in claim 2 in which the mixture of alkali metal oxides comprises Na 2  O and K 2  O. 
     
     
       6. A laser assembly as defined in claim 2 in which the mixture of alkali metal oxides is Na 2  O, Li 2  O and K 2  O. 
     
     
       7. A laser assembly as defined in claim 2 in which the heavy metal oxide is Sm 2  O 3 . 
     
     
       8. A laser assembly as defined in claim 2 in which the heavy metal oxide is CuO. 
     
     
       9. A laser assembly as defined in claim 2 in which the heavy metal oxide is CoO. 
     
     
       10. A laser assembly as defined in claim 2 in which the heavy metal oxide is FeO. 
     
     
       11. A laser assembly as defined in claim 2 in which the glass coating has the following approximate composition:   ______________________________________                                    
Ingredient       Percent By Weight                                        
______________________________________                                    
SiO.sub.2        11.9                                                     
Al.sub.2 O.sub.3 3.6                                                      
B.sub.2 O.sub.3  18.4                                                     
Li.sub.2 O       1.4                                                      
Na.sub.2 O       3                                                        
K.sub.2 O        0.6                                                      
CaO              0.8                                                      
ZnO              7.6                                                      
BaO              2.1                                                      
PbO              49.2                                                     
F.sub.2          0.3                                                      
CoO              5.45                                                     
MnO.sub.2        2.27.                                                    
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       12. A laser assembly as defined in claim 2 in which the heavy metal oxide is an oxide of a transition metal having an atomic number between 23 and 29.